The present invention relates to a large volume reactor or a thin film evaporator, and a method for processing a starting material in a large volume reactor or a thin film evaporator.
Large volume reactors or thin film evaporators are generally known and are used, among other things, in the production and/or processing of plastics.
Large volume reactors can be embodied, on the one hand, as kneaders or mixers such as is disclosed, for example, in the European Patent Application EP-A-1 477 223 or in the prior European Patent Application with the Application Number EP 05008591 which is published as European Publication No. EP 1 714 694 A1. These two documents disclose large volume reactors each having a plurality of reactor rotors. A large volume reactor with only one rotor is also known from the European Patent Application EP-A-1 417 998.
Thin film systems are known, for example, from EP-A-0 960 639 and DD-A-226 778.
In the known large volume reactors or thin film evaporators, a starting material or a plurality of starting materials is or are supplied via one or a plurality of product inlet openings to a reactor chamber of the large volume reactor or the thin film evaporator in which the starting material or the starting materials are processed by means of a reactor rotor. The starting materials can in this case be present as pure liquids, as at least partially gaseous components, as suspensions, as emulsions, as solutions, as pastes, as viscous melts, as granular solids, as fine solids, as foams or as a combination thereof.
The known large volume reactors or thin film evaporators have various disadvantages since the individual starting materials can either be supplied separately from one another or through the same reactor chamber inlet opening to the reactor chamber.
If a plurality of low viscosity starting materials are supplied to the reactor chamber of a kneader or a mixer, these low viscosity starting materials mix poorly since the reactor rotor turns relatively slowly, with the result that the two low viscosity starting materials can form two phases inside the reactor chamber which do not mix well with one another.
Furthermore, extremely small quantities of a second starting material, for example a catalyst, can be mixed only poorly into a much larger quantity of a first starting material by means of the known large volume reactors. If the second starting material is already mixed with the first starting material outside the reactor chamber, a reaction can begin outside the reactor chamber. This can result in a blockage in an intake to the reactor chamber. However, if the second starting material is supplied directly in the reactor chamber, the problem arises that the small quantity of the second starting material could only be mixed very poorly and slowly with the first starting material in the reactor chamber. This can result in an inhomogeneous product and/or large agglomerates in the reactor chamber since the first starting material can react strongly in parts or almost not at all with the second starting material. Large agglomerates result in a product having nonuniform properties. Furthermore, large agglomerates can result in thermal damage to the product since the heat produced during the reaction can only be removed very poorly. In addition, large agglomerates can result in impermissibly high mechanical loading of the reactor or the thin film evaporator.
If different starting materials which cannot be thoroughly mixed together are supplied to a mixer or a kneader, segregation effects can also occur in the reactor chamber.
Furthermore, the product quality is also negatively influenced if starting substances which react strongly with one another are fed into the reactor chamber via a plurality of reactor chamber inlet openings, since local concentration differences inside the reactor chamber can result in a nonuniform product quality.
Furthermore, as a result of exothermic reactions which take place when various starting materials are combined outside the large volume reactor, problems with the removal of the heat thereby produced can arise.
The known large volume reactors with a comparatively slowly rotating reactor rotor also exhibit problems if one of the starting materials is present in a gas phase and the other starting material is present in a liquid or a melt-like phase and the starting material present in the gas phase is to be dispersed in the starting material present in the liquid or melt-like phase.
With the known large volume reactors it is also difficult to incorporate fine granular material systems uniformly into a fluid phase.
It is accordingly an object of the present invention to provide a large volume reactor or a thin film evaporator which is free from the disadvantages of the prior art as discussed above.